Press



June 24, 1930. F. H. SMITH 1,766,265

' PRESS Original Filed Feb. 15, 1928 4 Sheets-Sheet l Qriginal Filed Feb. 15, 1928, 4 Sheets-Sheet 2 TIE. 2. f 3

Jupe 24, 1930. F. H. SMITH 1,

PRESS Original Filed Feb. 15, 192B 4 Sheets-Sheet 5 .1928 4 Sheets-Sheet 4 F. H. SMITH PRESS Original Filed Feb. 15

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cmceeo, rumors PRESS Application filed February 15, 1928. Serial No. 254,335. Renewed may 9, 1980..

This invention relates to presses for mold ing loose material, and more particularly to presses for molding loose granular or plastic material about a core to form hollow ar- 5 ticles, suchas bearings, bushings and the like. 7

Among the most important objectsof the invention is the provision of a press capable of applying heavy pressure to the material 10 in forming the hollow articles and by means i of which uniform density is impartedto the hollow articles, and further, to provide a press in ,which the articles are freed from the core and ejected from the moldchamber in such a manner as to avoid damage thereto.

A further object of the invention is to provide a. press of the character above referred to which operates continuopsly and rapidly without spilling the loose material from which the articles are molded.

A further object of the invention is to provide a mechanically operated press of the continuously reciprocating type in which the pressure to which the material is subjected may be'accurately regulated.

A further object of the invention is to provide a mechanically operated reciprocating press in which the material is molded under a predetermined pressure which is so maintained during a substantial portion of the stroke of the press.

A further object of the invention is to provide a press in which the mold chamber and core member are yieldably supported so that they may have a movement in the direction of movement of the pressure plunger while pressure is being applied to the material whereby the entire mass of material in the mold chamber is compressed with sub- 40 stantial uniformity so that the molded articles are of substantially uniform density throughout.

A ,further object of the invention is to provide a press in which opposed tubular plungers have a sliding fit on a central core member and within the mold chamber to compress material in the mold chamber surrounding the core member, in which means v is provided for simultaneously imparting vi= 5o brations to the core memberand a downmodifications thereof as will be ward movement to the lower of the tubular plungers to dispose the material in the mold chamber around the central core member without forcing-any ofthe loose material out of the mold chamber."

Having in view the objects above set forth and others which will appear as the description proceeds, the invention may be said to comprise the press as illustrated in the accompanying drawings hereinafter described and particularly set forth in the appended claims, together with such variations and apparent to one skilled in the art to which the invention appertains.

Reference .should be had to the accom 'panying drawings forming a part of this specificatiomin which Figure 1 is a sectional elevation in which the press is shown in section to the left of the vertical center line and in front eleva tion to the right of the center line. V

Fig. 2 is a sectional elevation showing the press in section to the right of the vertical center line and in side elevation to the left.

tegral cross members 3. The space-d side members of the frame provide guide-ways for a number of vertical movable crossheads. A mold crosshead 4 is mounted for limited vertical movement in guides 5 secured to the inner faces of the side members of the frame, and this crosshead carries a vertically dis-- posed mold chamber 6 which is in the form 'of a cylindrical bore extending through the crosshead.

the mold chamber surrounding,

Cooperating with the mold chamber 6 there is a cylindrical core member 7, which has a pointed upper end and which is of lesser diameter than the mold chamber. 6. The core member 7 is disposed coaxially with respect to the chamber 6 and is of a size to fit within a tubular pressure applying plunger 8 which moves downwardly into the mold chamber and onto the core member. Slidable upon the core member 7 there is a pressure receiving and ejecting plunger 9, which fits within the mold chamber 6 and closes the lower end of the annular space in the core member while the material is ing compressed in the space surroundin the core member and moves up to eject fire molded article after each compression stroke.

The pressure applying plunger 8 is fixed to a crosshead 10 which is mounted to slide in vertical guides 11 secured to the standards 2 of the frame. The pressure receiving plunger 9 is fixed to a crosshead 12 which is mounted to slide in vertical guides 13 secured to the side members of the frame be-- low the mold crosshead.

The core member 7 is fixed to a crosshead 14 which is mounted in the crosshead 12 in guides 15 permitting vertical movement of the crosshead 14 therein. Extending across the lower portion of the frame 1, and

through the crossheads 12 and 14, there is an operating shaft 16having a gear 17 fixed 'to one end thereof which is driven by a pimon 18 fixed to asuitable drive shaft 19.

' At its opposite ends this shaft 16 is provided with cranks 20 which are connected by means of connecting rods 21 with a crosshead 22 mounted in vertical guides 23 at the upper ends of the standards 2. The upper crosshead 22 has. fixed to the under side thereof a plunger 24 which slides in a vertical cylinder 25 carried by a cross member 26 fixed to the standards 2 and extending across the space between the same. The cylinder. 25 is a hydraulic c linder which is supplied with liquid throug a suitable pi e 27. "Extending into the lower end oftje cylinder 25 is a plunger 28 fixed to the pressure plunger crosshead 10.

Upon downward movement of the crosshead 22, pressure is transmitted from the plunger 24 through the liquid in the cylinder 25 to the plunger, 28 carried by the crosshead 10 to move the crosshead 10 in a downward direction. The crosshead 10 is lifted upon the upward movement of the crosshead 22 by means of tie rods 29-which are fixed to the crosshead 10 at their lower ends, and at their upper ends extend through the crosshead 22 and are connected to a cross bar 30 which carries an adjustablesto mem-. ber 31 which is engaged by the cross ead 22 upon upward movement of the "crosshead. The crosshead 22 is slidable on the tie rods,

the crosshead, it may. move away from the stop member 31, but upon upward movement of the crosshead, a direct lifting connection is provided through the members 31, 30 and tie rods 29. The mold crosshead 4 is fixed at its opposite ends to vertically disposed piston rods 32 which are connected to pistons 33 in neumatic cylinders 34 which are supplied with air under pressure throu h pipes 35. The pressure is admitted .to tie cylinders 34 below the istons so that the mold crosshead is norma 1y supported in its uppermost position, which is determined by the setting of stop screws 36 which engage with shoulders 37 at the lower ends of the crosshead guides 11. The crosshead 12 is attached to the upper ends of the piston rods 38 which are connected at their lower ends to pistons 39 of pneumatic cylinders 40 which have pressure supply pipes 41 for .admitting air under pressure to the spaces in the cylinders above the pistons 39. The core upon by pneumatic pressu e in the cylinder- 44 tending to hold it in it uppermost position. movements to the crosshead 12, a pair of cams 46 fixed to the operating shaft 16 engage with rollers 47 mounted in the crosshead 12 above the operating shaft, the cams 46 serving to lift the crosshead in opposition to the pneumatic pressure in the cylinders 40, the cylinders 40 serving by downward pressure on the crosshead 12 to press the rollers 47 against the earns 46 so that upward and downward movements are imparted to the crosshead 12 and plunger 9, the timing of the movements and the extent thereof being determined by the contour of the cams 46 which are of identical form. For .im arting downward movement to the cross ead 14, and core member 7 in opposition to the pneumatic pressure in the cylinder 44, a cam 48 is fixed to the operating shaft 16 midway between the cams 46, which engages with a roller 49 mounted in the crosshead 14 be-l neath the operating shaft '16. p All of the pneumatic cylinders above referred to preferably receive pressure from a common source, t e pipes 35 connected to the cylinders 34 and the pipes 41 and 45 connected to the cylinders 40 and 44 beingconnected to a supply line' 50, which communicates with a pressure supply tank 51 in In order to' impart reciprocating,

menses which a predetermined pressure is maintained by means of an automatically regulated compressor 52 which may be any one of the several standard types.

The purpose of the hydraulic cylinder interposed between the connecting crosshead 22 and the pressure plunger crosshead is to provide a connection between the mechanical actuating means and the plunger cross-' head which will yield upon pressure exceeding a predetermined amount to prevent damage to the plunger and mold and to prevent application of pressure to the material in the mold in excess of a predetermined amount. it is desirable, however, that there be no yielding between the actuating crosshead and the plunger crosshead at pressures below the predetermined pressure above mentioned and that the maximum pressure he maintained u on the material for an ap preciable time faring the strolre. To this end, liquid, which is an incompressible medium, is supplied to the cylinder 25 through the pipe 27 and means is provided for automatically permitting some of the liquid to be forced from the cylinder 25 when the pressure therein reaches av predetermined amount without reducing the pressure on the liquid. This is accomplished by means of a pneumatic pressure balancing device similar to that disclosed in patent to Smith and Nowalr No. 1,473,388 granted Nov. 6, 1923.

As shown in Fig. 8 ofthe drawi-n this pressure balancing device is indicated %y the numeral 53 and comprises a hydraplic cylinder 5% of relatively small diameter with which the pipe 27 communicates and a pneumatic cylinder 55 of a diameter relatively large with respect to that of the cylinder 54. A diilerential piston 56 is interposed he tween the cylinders 54 and 55 and has a small piston 57 fitting in the cylinder 54 and a large piston 58'fitting in the cylinder 55.

. sure in the cylinder 55.

The cylinder 55 is connected to the air pressure supply line 50 so that a predetermined pressure is maintained upon the large piston 58 which normally holds the differential piston 56 at its upper limit of movement. As the crosshead 22 moves downwardly, the plunger 24 acting throughthe liquid in the cylinder 25 forces a plunger 28 and crosshead 10 downwardly. As the downward movement with the crosshead 10 meets with resistance, pressure in the cylinder 25 gradually increases until the hydraulic pressure becomes sufiicient to force the piston 56 downwardly in opposition tothe air pres- Since the prion, matic pressure upon the under side of the large piston 58 is always the same, the downward movement of the plunger 24 with respect to the plunger 28 is accomplished without variation in the hydraulic pressure exerted on the plunger 28 so that during this relative movement, while the pressure plunportions 46, and d6 portion 48' to vibrate the ger 8 is moving at'a rate slower than the crosshead 22, or is stationary, the material in the mold is subjected to a constant ressure, the hydraulic cushion interpose between the mechanical actuating means and the pressure plunger causing the pressure plunger to act upon the material with constant pressure as in a hydraulic press so that the advantageous uniform pressure of a hydraullc press is obtained to other with the greater speed of operation due to mechanical reciprocation. In order to replace any liquid lost by leakage and to maintain the desired amount of li uid in the hydraulic chamber, the pipe 2 may be connected through a suitable valve with a liquid supply line 59. v telerrin to Figs. 3 to TI of the drawing, it will be 0 served that the cams'46 and i8 are so designed that when the lunger 8 is in its uppermost position a suficlent distance above the crosshead l to permit material to be led into the mold chamber, the crosshead 12 is in its uppermost position with the upper end, of the tubular plunger 9 substantially flush with the up or end of the mold chamber as shown in ig. 3 and with the core member 7, is in an intermediate position with its point sli htly below the to of the mold chamber so t at the VOlllmQlll'lC capacity of the tubular plunger 9 above the core member is just sufiicient to contain the amount of material necessary to form the article to be molded. It will be observed that the cam 46 is provided with dwell and with releasing 46 and 46. The

and lifting portions provided with a dwell porcam 48' is tion 48, depressing and releasing portions ed and 48 and a portion 48 of irregu- 18.2? or wavy contour for imparting vibra tiom to the core member 7. In Fig. 3 of the drawing, the cams46 have reached a position in which the rollers 47 are about to leave the dwell portion 46 and ride down the releasing portions 46 and the cam 4-8 has reached a position in which roller 49 is approaching the end of the dwell portion 48 and is about to be engaged by a wavy por-' tion 48. Continued rotation of the cams from the position shown in Fig. 3 causes the rollers 47 to move down the releasing portlons 46 of the cams 46, to lower the tubular lunger 9 to the position shown in Fig. d. himultaneously, the cam 48 has been turning .to cause the roller 49 to engage the wavy core member 7 while thetubular lunger 9 has been moving to the position adjacent the bottom of 'the mold chamber shown in Fig. 4. The vibration of the pore member causes the loose material in the mold chamber to settle into the space surrounding the core member 7 where it will be acted upon b the pressure plunger during its descent. he cranks 20 llf - matic pressure in the cy on the shaft 16 are so positioned with respect to the cams that-the downward movement of the pressure plunger 8 be 'ns while the plunger 9 is moving ownwar ly.

As the pressure plunger 8 moves into the mold, the roller 49 on the crosshead 14 engages with the releasing portion 48 of the cam 48 so that the core member is forced upwardly by the pneumatic pressure in the cylinder 44. While pressure is' being applied to the material in the mold, the ressure receiving plunger 9 is held in a ed position by the dwell portions 46 of the cams 46 and forms a fixed abutment against which the material in the mold is pressed, as shown in Fig. 5. The mold crosshead 4 and the core member 7, however, during the pressure stroke, are pressed upwardly by pneulinders 34 and 44 so that if there is excessive friction between the material being compressed and the surface of the chamber wall or of the core member, between the material and the surface, the crosshead 4 and'the crosshead 14, either or both, which are then yieldingly supported, may move in downward direction with the plunger 8 with the result that the pressure exerted on the materialXis applied with substantial uniformity throu hout the mass in the mold chamber and the tubular article formed in the chamber will have substantially uniform density throughout. During the downward stroke of the pressure plunger 8, the maximum pressure permitted by the pressure regulatin device 53 will be reached and maintaine duringthe remainder of the down stroke'and through as much of the return stroke of the actuating crosshead 22 as is required to enlarge the space to its uppermost position.

between the plungers 24 and 28 sufliciently to permit the differential plunger 56 to move During the return stroke of the plunger 8, the cam 48 reaches the position in which the depressing portion 48" engages the roller 49, forcing the core member 7 downwardly and the cams 46 reach a position in whic the lift portions 46 engage the rollers 47 so that while the compressed material is held between the plungers 8 and 9, the core member 7 is moved downwardly within the mold material'to break any adhesion between the surface of the core member and the inner surface of the mold article and at the same time, the plunger 9 follows the plunger 8 upwardly to slide the molded article in the mold member 6 and break any adhesion between the outer surface thereof and the surface of the mold chamber while the molded article is held between the plungers. During the final portion of the cycle, the plunger 8 reaches its uppermost position and the plunger 9 reaches a osi- 'on flush with the top of the cross 4 so that the molded article is completely .machine of the present invention ma ead ejected from the mold chamber. In the meantime, the core member. 7 has moved down to its lowermost position so. that simultaneously with the ejection of the molded article the parts are restored to the position for receivin a fresh charge of material', as shown in device (not shown) may be employed for depositing a char e of material in the mold and uslnng asi e the molded article -durin to interval in which the plunger 8 is he d in its uppermost position.

It will be apparent that the present invention provides a machine for rapidly and economically molding hollow articles from granular, powdered, plastic or other loose material, that the articles molded in the ma chine of the present invention will be of uniformly good quality by reason of the fact that they are com ressed to uniform density throughout an by reason of the fact that the molded articles are freed from the walls of the mold and core in such manner as to avoid marring of its surfaces.

Furthermore, it will be apparent that the be operated very rapidly without the dlsadvantages usually inherent in mechanically operated presses due to inequalities in pressure exerted on the work. In. addition, it will be noted that the press is of rugged construction throu'hout and employs only mechanical and uid ressure actuating elements capable of use or long periods without replacement or repair. 7

Furthermore it is to be understood that the particular form of a paratus shown and described, and the particular procedure set forth, are presented for purposes of explanation and illustration and that various modifications of said apparatus and cedure can be made without departing rom my invention as defined in the appended claims.

What I claim is:

1. In a press for molding loose material, a mold chamber having an open end, a core member mounted in said chamber, an ejecting plunger mounted in the chamber for movement toward and from the open end thereof, a pressure applying plunger .movable into and out of the 0 en end of the chamber and having .a sli ing fit in the chamber and on the core member, means for reciprocating the latter plunger and means for retracting the ejectin lunger and vibrating the core member film the pressure stroke and for advancing the ejecting plunger during the return stroke of the pressure applym plunger.

2. In a press or molding loose material, a mold chamber having an open end, a movable core member mounted in said chamber, a thrust receiving and ejecting plunger mounted in said chamber for. movement toig. 7. A suitable feed ward and from a position in which its end is substantially flush with the open end of said chamber and having a sliding lit within the chamber and on the core member, a pressure applying plunger movable into and out of the open end of the chamber and having a sliding fit in the chamber and on said core member, means for reciprocating the latter plunger, and means for retracting the ejecting plunger from the open end of the chamber and simultaneously vibrating the core member before the initial portion of the pressure stroke to dispose loose material in the chamber exteriorly of the core, and for retracting the core member to free the molded article therefrom and advancing the ejecting plunger to eject the article during the return stroke of the pressure applying plunger.

3. in a press for moldin tubular articles from loose material, a mol chamber having an open end, a core member disposed centrally of said chamber and movabletoward and from the open end thereof, a pressure applying plunger of tubular form mounted for movement mto'and out of the open end of said chamber and having a sliding fit in said chamber and on said core member, a thrust receivin and ejecting plunger mounted in the chamber for movement toward and from theopen end thereof and having a sliding lit in said chamber and on saidcore member, means for reciprocating said pres sure plunger, and means for retracting said ejecting plunger from the open end of the chamber and vibrating said core member before the pressure stroke of the ressure applying plun er, for advancing t e core member tower the open end during the pressure stroke, and for advancing said ejecting plunger toward the open end and retracting said core member therefrom during the return stroke of the pressure applying plunger.

'4. In a press for moldin tubular articles from loose material, a mold chamber having an open upper end, a vertical]. movable core member disposed centrally o the chamber, a bottom plunger slidably fitting within the chamber and on the core member, said b plun er being movable to] a position in whic its upper end is substantially flush with the upper end of the chamber, a to plunger mounted above the chamber an movable into and out of the same, the latter plunger having a sliding fit in the chamber and on thecore member, and means for reciprocating the top plunger means for moving the core member upwardly during the portion of the pressure stroke of the top plunger in which said plunger is-in said chamber, and means .for moving the bottom plunger upwardl and the core member downwardly during t e return stroke of the top plunger.

5. In a press for molding loose material, a mold chamber, a core member in said chamber, a pair of opposed plungers, each having a sliding fit in said chamber and on said core member, means for reciprocating said plungers, the stroke of the other and with their simultaneous movements in the same direction, one of said plunger-s being movable into and out of said chamber to permit entry of loose material thereto and the other of the plungers being movable in the chamber to the open end thereof to eject a molded article, and cushioning means interposed between one or said plungers and its actuating means.

6. in a press for molding loose material,

a movably mounted mold chamber, a core member in said chamber, a pair of opposed plungers, each having a sliding fit in said chamber and on said core members, means for reciprocating said plun are one with a strolre longer than the stro to of the other and with their simultaneous movements in the same direction, the first of said plungers being movable into and out of said chamber to permit entr of loose material thereto,

and the second plunger being movable in the chamber to the open end thereof to eject a molded article, and cushioning means for yieldingly pressing said mold chamber to-' ward said first plunger during the pressure stroke thereof.

7. in a press for molding loose material, a movably mounted mold chamber, a core member in said chamber, a pair ofo posed plungers, each having a sliding fit 1n said chamber and on said core members, means forreciprocating said plun ere one with a stroke longer than the stro e of the other and with their simultaneous movements in the same direction, one of said plun ers being movable into and out of said 0 amber ill) to permit entry of loose material thereto,

and the other of the lungers being movable in the chamber to t e open end thereof to eject a molded article, cushioning means for said mold chamber, and a fixed stop for limiting the movement of said mold cham- 8. Anpress for moldin loose material, a vertica y movable cross ead having a vertically disposed mold chamber therein open at its top, vertically movable cross heads above and below said first mentioned cross head, plungers carried by said cross heads axially alined with said mold chamber and formed to have a sliding fit therein, the upper plunger being movable into and out oil the mold chamber, means for reciprocating said upper and lower cross heads, a yieldi support for, the intermediate cross head, an yielding means interposed between one of said reciprocating cross heads and its actusting sans formed to have a sliding fit therein, the upper plunger being movable into and out of the mold chamber, means for reciprocating said upper and lower cross heads, a yielding support for the intermediate cross head, and hydraulic cushioning means interposed between one of the plungers and its actuating means.

10. In a press for molding loose material,

- a mold chamber having an open end through which loose material may be delivered thereto, a movable core member in said chamber, a pair of opposed plungers, each formed to fit within the chamber and on the core member, one movable into and out of the open end of the chamber and the other movable in the chamber toward and from the 0 en end thereof, means for actuating the rst mentioned plunger to compress loose material about the core member to form a molded article, means for reciprocating the first mentioned plun er to compress material in the chamber an for automatically limiting the pressure exerted on the material to a' predetermined amount, means for actuating said last mentioned plunger to eject the molded article, and means for simultaneously retracting the core member from the molded article.

' 11. In a press for molding loose material, a mold chamber having an open end through which loose material may be delivered thereto, a movable core member in said chamber, a pair of opposed plungers, each formed to fit within the chamber and on the core member, one movable into and out of the open end of the chamber and the other movable in the chambertoward and from the open end thereof, means for reciprocating the first mentioned plunger to compress loose material about the core member to form a molded article, means for moving the second plunger toward the opening to discharge a molded article and for moving said second plunger away from the opening during the interval in which the first plunger is out of second plun the mold chamber and means for movin the core member away from the open end of the chamber during said movement of the er toward the open end to permit entry 0 loose material to the interior of the second tubular plunger and for moving the core member toward the openin simultaneously with the movement of sai second plunger awa from the openin to eject loose-material rom the interior 0 the plunger into the mold chamber around the core member.

'movable into and out of the chamber, a

tubular lunger in the chamber having a sliding t within the chamber and on the core member, means for delivering material into the chamber when said plunger is at the upper end of its stroke, and means for simultaneousl vibrating the core member and moving t e tubular plun er down.

13. In a press for molding oose material, a vertically disposed-mold chamber, an n per plunger movable into and out of t e mold chamber, a tubular plunger slidable in the mold chamber, a core member within the tubular plunger, means for delivering loose material into the tubular plun er, and means for vibrating the core mem er and moving the tubular plunger down on the core member to eject the material from the tubular member into the chamber around the core member.

14. In a press for molding loose material, a vertically disposed mold chamber, an upper plunger movable into and out of the mold chamber, a tubular plunger slidable in the mold chamber, a core member within the tubular plunger, means for reciprocating the upper plunger, means for lowering the lower plunger at the beginning of the pressure strokeand raising the same during the return stroke of the upper plunger, an means for yieldingly supporting said core member and mold chamber.

15. In a press for molding loose material, a vertically disposed mold chamber, an u per plunger movable into and out of tie mold chamber, a tubular plunger slidable in the mold chamber, a core member within the tubular plunger, means for reciprocating the upper plunger, means for lowering the .lowerplunger at the beginning of the pressure stroke and raising the same during the return stroke of the upper plunger, means for yieldingl supportlng said core member and mold c amber, and means for cushioning the strokeof said upper plunger.

16. In a press for molding loose material,

a supporting frame, a cross. head mounted for limited vertical movement in said frame, pneumatic means for normally molding said cross head in its uppermost position, a vertically disposed mold chamber in said cross head, vertically movable cross heads mounted in said frame above and below said first mentioned cross head, tubular plungers carmeaaoa cushioned means for reciprocating the upper cross head, and means for mg the lower cross head.

18. In a press for molding loose material, a su porting frame, a cross head mounted reciprocatfor limited vertical movement in said frame,

pneumatic means for normally holding said cross head in its uppermost position, a vertically dis osed mold chamber in said cross head, vertically movable cross heads mounted in said frame above and below said first mentioned cross head, tubular plungers carried by said upper and lower cross heads adapted to have a sliding fit in said mold chamber, a core member within the lower plunger and supported independently thereo a crank shaft, and means connecting the crank shaft. to the upper cross head to actuate the same, pneumatic c linders connected to the lower cross hea and to said core member for actuatin each in one direction, and cams on said s aft for actuating the lower cross head and core member in opposition to said cylinders.

In testimony whereof I aflix my si ature.

FRANK H. S TH. 

